The Atacama Large mm and sub-mm Array (ALMA) radio observatory is one of the world’s largest astronomical
projects. After the very successful conclusion of the first observation cycles Early Science Cycles 0 and 1, the
ALMA project can report many successes and lessons learned. The science data taken interleaved with commis-
sioning tests for the still continuing addition of new capabilities has already resulted in numerous publications
in high-profile journals. The increasing data volume and complexity are challenging but under control. The
radio-astronomical data analysis package ”Common Astronomy Software Applications” (CASA) has played a
crucial role in this effort. This article describes the implementation of the ALMA data quality assurance system,
in particular the level 2 which is based on CASA, and the lessons learned.